Counter electrode for electrochromic devices

Abstract

The embodiments herein relate to electrochromic stacks, electrochromic devices, and methods and apparatus for making such stacks and devices. In various embodiments, an anodically coloring layer in an electrochromic stack or device is fabricated to include nickel tungsten tantalum oxide (NiWTaO). This material is particularly beneficial in that it is very transparent in its clear state.

What is claimed is: 
     
       1. An integrated deposition system for fabricating an electrochromic stack, the integrated deposition system comprising:
 a plurality of deposition stations aligned in series and interconnected and operable to pass a substrate from one station to the next without exposing the substrate to an external environment, wherein the plurality of deposition stations comprise
 (i) a first deposition station containing a first one or more material sources for depositing a cathodically coloring layer; 
 (ii) a second deposition station containing a second one or more material sources for depositing an anodically coloring layer comprising nickel tungsten tantalum oxide; and 
 
 a controller containing program instructions for passing the substrate through the plurality of deposition stations in a manner that deposits on the substrate (i) the cathodically coloring layer, and (ii) the anodically coloring layer to form a stack comprising at least the cathodically coloring layer and the anodically coloring layer. 
 
     
     
       2. The integrated deposition system of  claim 1 , wherein the nickel tungsten tantalum oxide has an atomic ratio of Ni:(W+Ta) that is between about 1.5:1 and 3:1. 
     
     
       3. The integrated deposition system of  claim 2 , wherein the nickel tungsten tantalum oxide has an atomic ratio of Ni:(W+Ta) that is between about 1.5:1 and 2.5:1. 
     
     
       4. The integrated deposition system of  claim 3 , wherein the nickel tungsten tantalum oxide has an atomic ratio of Ni:(W+Ta) that is between about 1.8:1 and 2.5:1. 
     
     
       5. The integrated deposition system of  claim 4 , wherein the nickel tungsten tantalum oxide has an atomic ratio of Ni:(W+Ta) that is between about 2:1 and 2.5:1. 
     
     
       6. The integrated deposition system of  claim 2 , wherein the nickel tungsten tantalum oxide has an atomic ratio of Ni:(W+Ta) that is between about 2:1 and 3:1. 
     
     
       7. The integrated deposition system of  claim 1 , wherein the nickel tungsten tantalum oxide has an atomic ratio of W:Ta that is between about 0.1:1 and 6:1. 
     
     
       8. The integrated deposition system of  claim 7 , wherein the nickel tungsten tantalum oxide has an atomic ratio of W:Ta that is between about 0.2:1 and 5:1. 
     
     
       9. The integrated deposition system of  claim 8 , wherein the nickel tungsten tantalum oxide has an atomic ratio of W:Ta that is between about 0.2:1 and 1:1. 
     
     
       10. The integrated deposition system of  claim 9 , wherein the nickel tungsten tantalum oxide has an atomic ratio of W:Ta that is between about 1:1 and 2:1. 
     
     
       11. The integrated deposition system of  claim 1 , wherein the nickel tungsten tantalum oxide has an atomic ratio of Ni:(W+Ta) that is between 1.8:1 and 3:1, and has an atomic ratio of W:Ta that is between 1:1 and 2:1. 
     
     
       12. The integrated deposition system of  claim 1 , wherein at least one of the second one or more material sources for depositing the anodically coloring layer comprise an elemental metal selected from the group consisting of: nickel, tungsten, and tantalum. 
     
     
       13. The integrated deposition system of  claim 1 , wherein at least one of the second one or more material sources for depositing the anodically coloring layer comprise an alloy comprising two or more metals selected from the group consisting of: nickel, tungsten, and tantalum. 
     
     
       14. The integrated deposition system of  claim 1 , wherein at least one of the second one or more material sources for depositing the anodically coloring layer comprise an oxide. 
     
     
       15. The integrated deposition system of  claim 1 , wherein the controller comprises instructions for passing the substrate through the plurality of deposition stations in a manner that deposits the anodically coloring layer as a substantially amorphous material. 
     
     
       16. The integrated deposition system of  claim 1 , wherein the controller comprises instructions for passing the substrate through the plurality of deposition stations in a manner that (1) deposits the cathodically coloring layer and the anodically coloring layer in direct physical contact with one another, and (2) converts a portion of the cathodically coloring layer and/or a portion of the anodically coloring layer to form an ion conducting and electrically insulating interfacial region between the cathodically coloring layer and the anodically coloring layer. 
     
     
       17. The integrated deposition system of  claim 1 , wherein the controller contains program instructions for depositing the anodically coloring layer as two or more sub-layers having different compositions and/or morphologies. 
     
     
       18. The integrated deposition system of  claim 1 , wherein the cathodically coloring layer comprises tungsten oxide WO x , wherein x is at least about 2.7 and is less than 3.0. 
     
     
       19. The integrated deposition system of  claim 1 , wherein the cathodically coloring layer comprises a bilayer or a graded layer, and wherein a portion of the cathodically coloring layer is superstoichiometric with respect to oxygen.